Electrode lead and secondary battery having the same

Abstract

An electrode lead for electrically connecting an electrode assembly provided inside a case of a secondary battery with the outside of the case, according to the present invention, comprises: an inner lead which is inserted between sealing parts of the case and to which an electrode tab of the electrode assembly is attached, and which has a gas flow path so as to allow gas to flow between the inside and the outside of the case; and an external lead which is insertably disposed in the gas flow path, is electrically connected with the inner lead when inserted into the gas flow path, seals one end of the gas flow path, and is separated from the gas flow path so as to cut off electrical connection with the inner lead when the pressure of the gas flowing into the gas flow path is greater than or equal to the predetermined pressure.

What is claimed is: 
     
       1. An electrode lead for electrically connecting an electrode assembly provided inside a case of a secondary battery to an outside of the case, the electrode lead comprising:
 an inner lead interposed between sealing parts of the case, to which an electrode tab of the electrode assembly is attached, and having a gas flow path formed to allow gas to move between inside and outside of the case; and 
 an outer lead constructed to be inserted into the gas flow path and electrically connected to the inner lead when inserted into the gas flow path, the outer lead which seals one end of the gas flow path and is separated from the gas flow path to cut off the electrical connection with the inner lead when pressure of gas flowed into the gas flow path is higher than or equal to a predetermined pressure. 
 
     
     
       2. The electrode lead according to  claim 1 , wherein the inner lead is formed such that an appearance of a part interposed between the sealing parts is a circular shape or an oval shape. 
     
     
       3. The electrode lead according to  claim 1 , wherein the inner lead is provided with a sealing member at a location where the inner lead comes into contact with the sealing part. 
     
     
       4. The electrode lead according to  claim 1 , wherein at least one of the inner lead and the outer lead is made of an electrically conductive material. 
     
     
       5. The electrode lead according to  claim 4 , wherein the electrically conductive material is at least one of copper, aluminum, nickel, iron, chrome, gold, and silver, or alloys thereof. 
     
     
       6. The electrode lead according to  claim 4 , wherein at least one of the inner lead and the outer lead is coated with an electrically non-conductive material on the electrically conductive material. 
     
     
       7. The electrode lead according to  claim 1 , wherein at least one of the inner lead and the outer lead comprises an electrically conductive material on an electrically non-conductive material to establish an electrical connection from one end to the other end. 
     
     
       8. The electrode lead according to  claim 1 , wherein either a cathode tab or an anode tab of the electrode assembly is attached to the inner lead. 
     
     
       9. The electrode lead according to  claim 1 , wherein both a cathode tab and an anode tab of the electrode assembly are attached to the inner lead. 
     
     
       10. The electrode lead according to  claim 1 , wherein the inner lead has an attachment area formed for attachment of the electrode tab. 
     
     
       11. The electrode lead according to  claim 10 , wherein the inner lead is welded to the electrode tab at the attachment area. 
     
     
       12. The electrode lead according to  claim 1 , wherein the gas flow path has an electrode assembly side end of a cross sectional area becoming wider in a direction toward the electrode assembly. 
     
     
       13. The electrode lead according to  claim 1 , wherein an outer surface of an inside end of the inner lead is adhered to an inner surface of the case. 
     
     
       14. The electrode lead according to  claim 1 , wherein the outer lead is formed such that an outside of a part inserted into the gas flow path is wider than the part inserted into the gas flow path. 
     
     
       15. The electrode lead according to  claim 1 , further comprising:
 a ring-type packing member between the outer lead and the inner lead. 
 
     
     
       16. The electrode lead according to  claim 1 , wherein the inner lead has at least one gas flow path. 
     
     
       17. The electrode lead according to  claim 1 , wherein a protrusion or a groove is formed in the gas flow path of the inner lead and the outer lead, and the protrusion is coupled with the groove. 
     
     
       18. A secondary battery comprising the electrode lead according to  claim 1 . 
     
     
       19. The secondary battery according to  claim 18 , wherein the electrode lead is at least one of a cathode lead and an anode lead. 
     
     
       20. The secondary battery according to  claim 18 , wherein the case has a shape of a pouch. 
     
     
       21. A battery pack comprising the electrode lead according to  claim 1 .